1. Field of Invention
The present invention relates to a method and apparatus for producing control signals which can be used to control various types of equipment in work or recreational environments.
2. Brief Description of the Prior Art
The use of hand-actuable controllers to control equipment, such as transmissions, is well known in the art.
One Exemplary prior art controller is disclosed in the paper "User-Friendly Electronic Power Shift Transmission Controls" by Garth H. Bulgrien, SAE Technical Paper No. 911831, September, 1991. This controller employs a single shift lever assembly, a 16-bit microprocessor, random access memory, read only memory for storing a transmission control program, and an LCD indicator for visually indicating forward, neutral, and reverse directions, and gear ratios 1 through 18 selected by the operator. The transmission control program in this prior art controller generates controls signals for solenoid values which control multi-disc hydraulic clutches in the power-shift transmission. The design of the power-shift transmission provides 18 forward and 9 reverse gear ratios. The single shift lever is used to select all 27 transmissions ratios and has detented forward, neutral, and reverse positions. In each of these three positions, the lever can be moved to momentary upshift and down shift positions. In addition, there is a neutral latch which is released by raising a collar under the shift knob.
Prior art controllers of the type described above use conventional electro-mechanical switches to detect the various control positions manually selected by the operator. While highly functional, these electro-mechanical switches have less than optional reliability and an operational life commonly limited to one or two million cycles. As these devices are generally difficult and expensive to electrically interface, it is difficult to automatically detect their malfunction. Also, due to the large number of electro-mechanical switches required in any particular application, such prior art controllers have been inherently expensive to manufacture.
In order to overcome the above-described drawbacks associated with prior art controllers, the I-MAXX, ELECTRO-MAXX, and MORSE TCU brand controllers from IMO Industries each utilize Hall-effect sensing technology in lieu of conventional electro-mechanical switches. While these prior art controllers can be adapted to control various types of transmissions, the movement of their shift levers is limited to a single axis for the purpose of selecting forward, neutral and reverse directions and gear ratios. When provided with five or more forward and/or reverse gear ratio selections, a controller of this type requires extensive shift lever movement which can often cause operator fatigue over prolong periods of use.
Thus, there is a great need in the art for an improved method of producing control signals from a compact, hand-actuable controller which is reliable, programmable, and permits selection of a relatively large number of forward and reverse gear ratios in a safe manner, while minimizing hand movement operations.